Improve ocl cvt_color performance for the following conversions: RGB<->BGR, RGB->Gray, RGB<->XYZ, RGB<->YCrCb, RGB<->YUV, and mRGBA<->RGBA.
The improvement was done basically by processing more than 1 pixel by each work-item and using vector's operations.
new performance tests were added

Added "sep_filter_singlepass" kernel that performs separable filtering in one kernel call
Added appropriate host part - sepFilter2D_SinglePass function and SingleStepSeparableFilterEngine_GPU class
Changed function declarations to enable their usage

There are some mixed implicitly/explicitly type conversion between
scalar and vector. Although the spec allows those conversion, I prefer
to make them consistent and use explicitly all the cases.
Signed-off-by: Zhigang Gong <zhigang.gong@intel.com>

Some of functions were enabled on Qualcomm S800 by changing grid size;
OpenCL kernel grid size unification for different platfroms;
Test pass rate improvements by inclreasing threshold;
Some tests were disabled for Android;
run.py was adopted for devices with brackets in in name.